Pesticide Sprayer Calibration, Use and Care

• Don’t Overlook Backpack Sprayers for Small Scale Farmers [5:38] - Farmers tend to underestimate what backpack sprayers can do for them to improve their operations, their profitability, and their efficiency. Knowing the differences between sprayer models will help you select the sprayer that will work best for you on your farm or operation.

• Choosing the Right Sprayer to Enhance Spray Application and Reduce Fatigue: Comparing Two Styles of Backpack Sprayers [2:33] - The size of a sprayer’s piston pump combined with the pump’s leveraging system style has a big impact on the sprayer’s ease of use. In this video, use of a sprayer with a large internally mounted piston pump is demonstrated in comparison to a sprayer with a small externally mounted piston pump. 

• Reviewing Gasoline Powered Backpack Sprayers: Do They Enhance Sprayer Performance? [3:05] - While manually operated backpack sprayers are most commonly used, gas powered models are also available and may be the right fit for your needs. This video discusses how these sprayers function differently from manually operated models.

• Conversion Steps for Backpack Sprayers: Improving Accuracy by Addressing the “disconnect between sprayer manufacturers and sprayer accessories suppliers” [8:47] - Modifying your backpack sprayer wand to accommodate an array of different nozzle types will give you lots of options for customizing your spray delivery. The video provides step-by-step instructions for converting your spray wand to a system that will allow you to select the best nozzle for each job.

• It’s All in the Nozzle: Comparing Recent and Older Spray Nozzle Designs Addressing Various Spray Requirements [9:05] - Using a nozzle that delivers smaller spray droplets will improve the coverage you can achieve, however using a nozzle that delivers larger droplets will reduce potential for spray drift. In addition to droplet size, different nozzles provide options such as multiple spray angles, wider swath widths, and uniform droplet size. This video discusses nozzle types and the situations in which one may be preferable over another.

Backpack Sprayer Calibration

Sprayer calibration is key to efficient, accurate, and safe spraying. This collection of resources demonstrates the steps to calibrating a backpack sprayer using the “1/128th method”, discusses important factors to consider regarding safety, nozzle selection and maintenance, and provides a worksheet with video guidance that can be used to work through the calibration calculations and record keeping.

• Backpack Sprayer Calibration [7:28] - This video provides an overview of how to use a backpack sprayer and how to calibrate that sprayer to deliver a known amount of product.   

• Backpack Sprayers Apply Liquid Products Accurately with Proper Calibration [6:20] - Calibration is a necessary step in order to apply the correct amount of product.  This video discusses the three factors affecting calibration and strategies to ensure accurate calibration.

1/128th Method of Calibration

This collection of resources demonstrates the steps to calibrating a backpack sprayer using the “1/128th method”, discusses important factors to consider regarding safety, nozzle selection and maintenance, and provides a worksheet with video guidance that can be used to work through the calibration calculations and record keeping. 

• Backpack Sprayer Calibration: 1/128th Method Worksheet [worksheet]
  Hoja de trabajo de Calibración de rociador de mochila_ Método 1_128 [hoja de cálculo]

• Using the Backpack Sprayer Calibration Worksheet: 1/128th Method [9:28]

"Actual Area" Sprayed Method of Calibration

In some situations, the ’Actual Area Sprayed’ method of backpack sprayer calibration will give the most accurate results.  This collection of resources will help you work through the steps of calibrating your backpack sprayer, including guidance on measurements, calculations, and record keeping.

• Backpack Sprayer Calibration Worksheet: Actual Area Sprayed Method [worksheet]
  Hoja de trabajo de Calibración de rociador de mochila - Método de área rociada real [hoja de cálculo]

• Using the Backpack Sprayer Calibration Worksheet: Actual Area Sprayed Method [6:11]

For an in-depth look at how to select, use, and maintain backpack sprayers and nozzles, two one-hour webinar-style classes are available. These classes offer one NH pesticide applicator credit per course.

• Using Backpack Sprayers – Part One [course]

• Using Backpack Sprayers – Part Two [course]

Mixing Pesticide Solutions

When preparing to mix pesticide solutions, you may find that the label instructions on the particular product you are planning to use are based on larger application areas and larger volumes of spray solution than what your job requires. Additionally, pesticide product label instructions differ in how mixing rates are presented. Use these worksheets to convert rates designed for large areas to equivalent rates for smaller areas. Choose the worksheet that coincides with the rate format in the label instructions for the product you are using.

• Preparing Small Volumes of Spray Solution: Amount of Product per Acre - Use this calculation worksheet and video if the instructions on your product label are presented as an amount of product per acre. (i.e.: pints/acre, quarts/acre, fl oz/acre, or lbs./acre)  

  • Worksheet

  • Video [6:56]

• Preparing Small Volumes of Spray Solution: Amount of Product per 1,000 Square Feet Calculation Worksheet - Use this calculation worksheet if the instructions on your product label are presented as an amount of product per 1,000 square feet.  (i.e.: pints/1000 sq ft, quarts/1000 sq ft, fl oz/1000 sq ft, or lbs/1000 sq ft) 

• Preparing Small Volumes of Spray Solution: Amount of Product per Gallon Calculation Worksheet - Use this calculation worksheet when the instructions on your product label are presented as an amount of product per gallon of spray solution.  (i.e.: tablespoons/gal, teaspoons/gal, fl oz/gal, or oz/gallon) 

• Preparing Small Volumes of Spray Solution: Amount of Product per ‘X’ (Multiple) Number of Gallons - Use this calculation worksheet and video when the instructions on your product label are presented as an amount of product per some number of gallons of spray solution.  (i.e.: lbs/100 gallons, quarts/10 gallons, ounces/5 gallons) 

  • Worksheet

  • Video [7:17]

• Preparing Small Volumes of Spray Solution: Percent Solution Calculation Worksheet - Use this worksheet when the instructions on your product label are presented as a percentage solution. (Example: “Apply at a rate of 1.0 - 2.0% in sufficient amounts of water to achieve complete coverage.”) 

• How to Accurately Measure Small Quantities of Spray Products for Backpack Sprayers [3:28] - Preparing spray products for use in a backpack sprayer requires that you have a system for accurately measuring out small quantities of chemicals. This video describes low-cost tools and strategies for measuring small amounts of liquids and dry products.

• Measurements for Pesticide Application - When mixing small volumes of pesticide solutions, you may need to convert the units listed on the product label into smaller, more precise measurements. This reference sheet provides quick, accurate conversions to help ensure proper dilution and safe, effective application. Keep it on hand whenever you're preparing pesticide mixes. Always follow the label directions and precautions of the material being used.   

• Spray Rate Conversions - When calibrating your sprayers and preparing spray mixtures, you may find that you need to convert units between gallons per acre, gallons per 1,000 square feet, and fluid ounces per 1,000 square feet.  This conversion table is a handy reference for quickly converting between these rates. 

Quick Tips for Using Your Backpack Sprayer 

• Selecting the Right Backpack Mist Sprayer [1:37] - The right backpack mist sprayer for the job may depend on where you will be spraying.  If you will be spraying areas above shoulder height, a pump-assisted sprayer, rather than a gravity-fed sprayer will get the job done. In this video, George Hamilton discusses the differences in how these two sprayer types work.
• Control Flow Valve [1:26] - Keeping a consistent pressure in the tank ensures uniform delivery of your spray.  In this video, George Hamilton shows how use of a dual compensating pressure control flow valve provides for consistent spray application regardless of how fast or slow you pump the tank.
• Putting on Your Sprayer [1:06] - A filled backpack sprayer is heavy and awkward to put on. Using care when putting on your backpack sprayer is important for avoiding injury.  In this video, George Hamilton demonstrates how to put on a backpack sprayer without dangerously twisting or straining your back.
• Distance to Target [1:09] - Your owner’s manual will tell you how far you should hold the nozzle tip from your target. By marking the correct nozzle height on a table leg or other stationary object, you can easily gauge how high you will need to hold your wand in order to keep the nozzle at the right distance from the target.  In this video, George Hamilton demonstrates how he uses this tip when he is preparing to spray with a backpack sprayer.
• Clearing a Clogged Nozzle [1:05] - A common problem when working with backpack sprayers is a clogged nozzle.  In this video, George Hamilton demonstrates how to safely and effectively clear a clogged nozzle so that you can return to spraying at the intended rate and coverage.
• Taking Proper Notes [1:05] - With any type of sprayer, referring to your records of sprayer calibration is an important step in ensuring accuracy of your application rates.  In this video, George Hamilton provides tips on keeping your calibration records easily accessible.
• Winterizing Your Sprayers - As winter approaches, it’s important to winterize your spray equipment so it will be in good condition and ready to use for the next season.

Applications in Greenhouses and Nurseries

• Greenhouse Spraying Basics [10:09] - Learn the essential steps for effective and safe pesticide application in greenhouse settings. This video covers key terms, equipment prep, proper mixing and application techniques, coverage and canopy penetration tips, and post-application cleaning procedures. Ideal for greenhouse professionals looking to improve application accuracy, reduce waste, and stay compliant with safety best practices. 

• Greenhouse Sprayer Calibration and Spray Calculation - Use this worksheet and video to calibrate a sprayer for use in greenhouses, nurseries, or when the label rate is given in amount of pesticide per 100 gallons of spray. Application rates for pesticides labeled for use in fields are usually given in amount of pesticide per acre. By contrast, pesticides labeled for use in greenhouses and nurseries usually state application rates in amount of pesticide per 100 gallons of spray volume. This gives the greenhouse or nursery applicator greater flexibility to alter the amount of pesticide applied to a given area based on plant size and density. As such, however, determining how much spray to mix and how to calibrate a sprayer for a greenhouse or nursery application requires a different procedure than those shown above for other backpack sprayer applications.  

  • Worksheet

  • Video [9:17]

• Using Your Injector for Pesticide Applications [41:07] - Injectors can be a convenient and affordable way to provide a drench to containerized crops. Learn how to properly calculate, mix and deliver a drench using a proportional injector in this webinar recording.

• Delivering a Drench Using an Injector Worksheet - Injectors are a convenient and affordable way to provide a drench to containerized crops, but this method must be calculated and calibrated properly.  This worksheet will walk you through the steps.